BRAKE LIGHT REPAIR


Q:

The brake lights on my 1959 Corvette are doing some kind of wicked magic now days. Sometimes they work, and sometimes they don’t. I have changed the bulbs several times. I have checked the wiring. I have even had a mechanic check the wiring, and it works for a while, but it always seems to go back to the same problem. I have tried everything with no success. I hope the car isn’t haunted. Can you possibly help me figure it out?


A:

The problem with your brake lights working intermittently is most probably caused by wear in your turn signal switch mechanism. Please be aware that the electric turn signal switch, in your turn signal housing, just under your steering wheel, does two things whenever you make a turn. One of those things is to disconnect the brake light circuit on the side of the car where you want the turn signals to flash. Since the brake lights and the turn signal lights share the same filament in the tail lamp housing, you must realize that, if the brake light is on, as it would be if you were waiting at a stoplight with your foot on the brake pedal, the turn signal light couldn’t work on that same filament.


Therefore, the turn signal switch must first turn off the brake light on that side of the car, and then connect the turn signal flasher circuit. When it does that, the brake light will remain lighted on the other side of the rear of the car, and the turn signal lamps will flash on the correct side. The turn signal switch is made in such a way that one side is used for right turns, the other side is used for left turns, and off is in the center. After the turn is complete, and the turn signal switch cancels, stopping the flashers; the turn signal switch must fully return to the center, off position, in order to re-energize the brake light that it had disconnected. If it doesn't return all the way to the center, only one brake light will work. I think this is what you are experiencing.


This problem is most often caused by wear between the flat leaf spring and the two pins that it contacts, in the turn signal switch housing under your steering wheel. After disconnecting the battery and removing the steering wheel to gain access to the turn signal switch housing, you can see the turn signal ring. It is a die cast ring in the turn signal housing, about three inches in diameter. It is hollow in the center, and the turn signal operating handle is screwed into the left side of it. Under that ring, facing down away from you, there are two round pins, which are a part of the turn signal ring. They bear against a flat leaf spring that stands up on edge, held in slots below. When the leaf spring wears in its mounting slots, it will not have sufficient tension and contact with the two pins to completely return the electrical switch to the center, off position after a turn.


An easy fix is to go to a hobby shop and buy a piece of hollow brass tubing measuring one quarter inch on the outside diameter. The wall thickness is about .0175 inches. This brass tubing is sold in many different sizes. As a matter of fact, you could buy a series of them, each one just a size away from the last, and fit them together like a telescoping radio antenna. Cut off two small pieces of this tubing with a tubing cutter. They should be about 5/16" long each. Using a small vise, like a drill press vise, push one of these short lengths of tubing over each of the pins on the underside of the turn signal ring. This will make the pins slightly larger in diameter. The larger diameter pins will contact the leaf spring in such a way as to re-establish the correct tension that is necessary to operate the proper canceling movement.


That increase in diameter will help take up for the wear that has occurred over the years. When you put the parts back together again, you will find that the turn signal canceling mechanism will cancel smartly after each turn, thereby centering the turn signal switch and restoring operation of both brake lights.